Methods of manufacturing semiconductor devices by forming source/drain regions before gate electrode separation

ABSTRACT

Spaced apart first and second fins are formed on a substrate. An isolation layer is formed on the substrate between the first and second fins. A gate electrode is formed on the isolation layer and crossing the first and second fins. Source/drain regions are formed on the first and second fins adjacent the gate electrode. After forming the source/drain regions, a portion of the gate electrode between the first and second fins is removed to expose the isolation layer. The source/drain regions may be formed by epitaxial growth.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of U.S. patent application Ser. No.14/803,893 filed on Jul. 20, 2015 in the United States Patent andTrademark Office which claims priority to Korean Patent Application No.10-2014-0149483 filed on Oct. 30, 2014 in the Korean IntellectualProperty Office which claims priority to US provisional application No.62/026,948 filed on Jul. 21, 2014 in the United States Patent andTrademark Office, and all the benefits accruing therefrom under 35U.S.C. 119, the contents of which are herein incorporated by referencein their entirety.

BACKGROUND

1. Field of the Invention

The present inventive concept relates to semiconductor devices andmethods of manufacturing the same and/or particularly methods ofmanufacturing semiconductor devices with multi-gate transistorstructures.

2. Description of the Related Art

Techniques for increasing the density of semiconductor devices includeforming multi-gate transistor structures including a silicon body of ananowire shape or a fin shape, and a gate surrounding the silicon body.Such a structure may be scaled relatively easily, as the multi-gatetransistor structure uses a three-dimensional channel. Current controlcapability of such a device can be improved without increasing a lengthof the gate. In addition, short channel effect (SCE), which involves apotential of the channel region being affected by the drain voltage, canbe effectively suppressed.

SUMMARY

Some embodiments of the present inventive concept provide methods ofmanufacturing semiconductor devices that can improve performance byreducing failures of sidewalls of a gate, a source or a drain.

Some embodiments of the inventive concept provide methods ofmanufacturing semiconductor devices including forming spaced apart firstand second fins on a substrate, forming an isolation layer on thesubstrate between the first and second fins, forming a gate electrode onthe isolation layer and crossing the first and second fins, formingsource/drain regions on the first and second fins on first and secondsides of the gate electrode, and removing a portion of the gateelectrode between the first and second fins to expose the isolationlayer after forming of the source/drain regions. The source/drainregions may be formed, for example, by epitaxial growth.

In some embodiments, forming the gate electrode may include forming agate insulation layer on the first and second fins, forming a gateelectrode layer on the gate insulation layer, and forming a hard masklayer on the gate electrode layer. Forming the gate electrode mayfurther include patterning the hard mask layer to form a hard maskpattern and patterning the gate insulation layer and the gate electrodelayer using the hard mask pattern as a mask.

In some embodiments, forming the source/drain regions on the first andsecond fins may be followed by removing the gate electrode and forming agate structure including a first metal layer and a second metal layer.

In further embodiments, the methods may include forming spacers onlateral surfaces of the gate electrode and on lateral surfaces of thefirst and second fins. Forming source/drain regions on the first andsecond fins adjacent the gate electrode may be preceded by removingportions of the first and second fins to recess upper surfaces of thefirst and second fins below the spacers and forming source/drain regionson the first and second fins on first and second sides of the gateelectrode may include forming the source/drain regions on the recessedupper surfaces of the first and second fins.

In some embodiments, removing portions of the first and second fins torecess upper surfaces of the first and second fins below the spacers mayinclude forming an interlayer insulation layer covering the second finand exposing a portion of the first fin, removing a portion of theexposed first fin to recess the upper surface of the first fin, forminga second interlayer insulation layer covering the first fin and exposinga portion of the second fin, and removing a portion of the exposedsecond fin to recess the upper surface of the second fin.

Some embodiments, the first fin may be part of a PMOS transistor and thesecond fin may be part of an NMOS transistor. The source/drain regionsinclude a SiGe source/drain region on the first fin and a Si or SiCsource/drain region on the second fin.

Further embodiments of the inventive concept provide methods includingforming spaced apart first and second fins on a substrate, forming anisolation layer on the substrate between the first and second fins,forming a dummy gate on the isolation layer and crossing the first andsecond fins, forming source/drain regions on the first and second finson first and second sides of the dummy gate, removing the dummy gate toform a trench, forming a gate structure in the trench, and removing aportion of the gate structure between the first and second fins to formrespective first and second gate structures on respective ones of thefirst and second fins. The gate structure may include a gate insulationlayer, a first metal layer and a second metal layer, and the gatestructure may be formed after formation of the source drain regions.

Still further embodiments provide methods including forming a fin on asubstrate and extending longitudinally along a first direction, forminga conductive region extending longitudinally along a second directiontransverse to the first direction and crossing the fin, forming firstand second source/drain regions on the fin at locations on respectivefirst and second sides of the conductive region, and removing a portionof the conductive region adjacent the fin after forming the first andsecond source/drain regions to form a gate electrode of a transistorincluding the first and second source/drain regions and a channel in thefin.

In some embodiments, forming a conductive region extendinglongitudinally along a second direction transverse to the firstdirection and crossing the fin may include forming a dummy regionextending longitudinally along the second direction transverse to thefirst direction and crossing the fin prior to forming the first andsecond source/drain regions, removing the dummy region after forming thefirst and second source/drain regions to form a trench, and forming theconductive region in the trench.

In some embodiments, forming first and second source/drain regions onthe fin at locations on respective first and second sides of theconductive region may be preceded by forming spacers on sidewalls of thefin and removing first and second portions of the fin to recess firstand second surfaces of the fin below the spacers. Forming first andsecond source/drain regions on the fin at locations on respective firstand second sides of the conductive region may include forming the firstand second source/drain regions on the recessed first and secondsurfaces. The first and second source/drain regions may be formed byepitaxial growth.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventiveconcept will become more apparent by describing in detail exampleembodiments thereof with reference to the attached drawings in which:

FIGS. 1 to 16 are diagrams illustrating intermediate process steps formanufacturing a semiconductor device according to first embodiments ofthe present inventive concept;

FIGS. 17 to 20 are diagrams illustrating intermediate process steps formanufacturing a semiconductor device according to second embodiments ofthe present inventive concept;

FIGS. 21 to 29 are diagrams illustrating intermediate process steps formanufacturing a semiconductor device according to third embodiments ofthe present inventive concept;

FIGS. 30 to 32 are diagrams illustrating semiconductor devices accordingto some example embodiments of the present inventive concept;

FIG. 33 is a schematic diagram illustrating a memory cell according tosome example embodiments of the present inventive concept;

FIGS. 34 and 35 are plan views illustrating semiconductor devicesaccording to some example embodiments of the present inventive concept;

FIG. 36 is a schematic block diagram illustrating an electronic systemincluding semiconductor devices according to some example embodiments ofthe present inventive concept;

FIG. 37 is a schematic block diagram illustrating an application exampleof an electronic system including semiconductor devices according tosome example embodiments of the present inventive concept; and

FIGS. 38 to 40 illustrate example systems including semiconductordevices according to some example embodiments of the present inventiveconcept.

DETAILED DESCRIPTION

Advantages and features of the present inventive concept and methods ofaccomplishing the same may be understood more readily by reference tothe following detailed description of example embodiments and theaccompanying drawings. The present inventive concept may, however, beembodied in many different forms and should not be construed as beinglimited to the embodiments set forth herein. Rather, these exampleembodiments are provided so that this disclosure will be thorough andcomplete and will fully convey the concept of the inventive concept tothose skilled in the art, and the present inventive concept will only bedefined by the appended claims. Like reference numerals refer to likeelements throughout the specification.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting of theinventive concept. As used herein, the singular forms “a”, “an” and“the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. It will be further understood thatthe terms “comprises” and/or “comprising,” when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

It will be understood that when an element or layer is referred to asbeing “on”, “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layeror intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on”, “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, region, layer or section fromanother region, layer or section. Thus, a first element, component,region, layer or section discussed below could be termed a secondelement, component, region, layer or section without departing from theteachings of the present inventive concept.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper”, and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the example term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

Example embodiments are described herein with reference to cross-sectionillustrations that are schematic illustrations of idealized exampleembodiments (and intermediate structures). As such, variations from theshapes of the illustrations as a result, for example, of manufacturingtechniques and/or tolerances, are to be expected. Thus, these exampleembodiments should not be construed as limited to the particular shapesof regions illustrated herein but are to include deviations in shapesthat result, for example, from manufacturing. For example, an implantedregion illustrated as a rectangle will, typically, have rounded orcurved features and/or a gradient of implant concentration at its edgesrather than a binary change from implanted to non-implanted region.Likewise, a buried region formed by implantation may result in someimplantation in the region between the buried region and the surfacethrough which the implantation takes place. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the actual shape of a region of a device andare not intended to limit the scope of the present inventive concept.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which the present inventive conceptbelongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand this specification and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Hereinafter, operations for manufacturing semiconductor devicesaccording to some example embodiments of the present inventive conceptwill be described with reference to FIGS. 1 to 40. FIGS. 1 to 16 arediagrams illustrating intermediate process steps for manufacturing asemiconductor device according to first embodiments of the presentinventive concept.

Specifically, FIG. 1 illustrates forming fins using a mask pattern, andFIG. 2 illustrates a cross-sectional view taken along the line A-A ofFIG. 1. Referring to FIGS. 1 and 2, fins F1 to F4 are formed on asubstrate 100. The substrate 100 may include a first region I and asecond region II. The substrate 100 may include, for example, bulksilicon or silicon-on-insulator (SOI). In some embodiments, thesubstrate 100 may be a silicon substrate, or a substrate made of othermaterials, such as germanium, silicon germanium, indium antimonide, leadtelluride compound, indium arsenide, indium phosphide, gallium arsenide,and/or gallium antimonide. In some embodiments, the substrate 100 mayinclude a base substrate and an epitaxial layer formed on the basesubstrate.

The fins F1 to F4 may extend lengthwise along a second direction Y onthe substrate 100. The fins F1 to F4 may be portions of the substrate100 or may include an epitaxial layer grown from the substrate 100. Forexample, the first region I may include a first fin F 1 and a second finF2 extending along the second direction Y and the second region II mayinclude a third fin F3 and a fourth fin F4 extending along the seconddirection Y.

The fins F1 to F4 may be formed using a mask pattern 105 formed on thesubstrate 100. The mask pattern 105 may include, for example, siliconoxide, silicon nitride, silicon oxynitride, a metal layer, a photoresist, spin on glass (SOG), and/or a spin on hard mask (SOH). The maskpattern 105 may be formed using, for example, a physical vapordeposition process (PVD), a chemical vapor deposition process (CVD), anatomic layer deposition (ALD) and/or spin coating.

The fins F1 to F4 may be formed by an etching process using the maskpattern 105. Respective bottom portions of the fins F1 to F4 may bewider than respective top portions thereof. In other words, the fins F1to F4 may have widths increasing downwardly. It will be appreciated thatembodiments of inventive concept are not limited thereto.

Referring to FIG. 3, an isolation layer 110 is formed between respectiveones of the fins F1 to F4. The isolation layer 110 is formed in thesubstrate 100 to define an active region (not shown) of thesemiconductor device. The isolation layer 110 may include a shallowtrench isolation (STI) or a deep trench isolation (DTI) structure, whichmay be advantageous for high integration owing to isolationcharacteristics and a small area occupied. It will be appreciatedhowever, that embodiments of the present inventive concept are notlimited thereto. The isolation layer 110 may include, for example,silicon oxide, silicon nitride, silicon oxynitride, or combinationsthereof.

The isolation layer 110 is formed on the substrate 100, and aplanarization process (e.g., CMP) is performed to planarize a topsurface of the isolation layer 110 and top surfaces of the fins F1 toF4. Accordingly, the top surface of the isolation layer 110 and the topsurfaces of the fins F1 to F4 may be coplanar.

Referring to FIG. 4, a top portion of the isolation layer 110 is etchedusing an etching process. The isolation layer 110 may be etched to afirst depth. In the etching process of the isolation layer 110,materials having different etching selectivity levels may be used.Therefore, only the top portion of the isolation layer 110, except forthe fins F1 to F4 and the substrate 100, may be etched. The etchingprocess may include, for example, a dry etching process and a wetetching process, but embodiments of the present inventive concept arenot limited thereto.

Referring to FIG. 5, the isolation layer 110 resulting after the etchingprocess may have a concave or convex upper surface, rather than a planarupper surface. For example, more etching may occur to side portions ofthe isolation layer 110 near the fins F1 to F4 than to center portionsof the isolation layer 110 between the fins F1 to F4. Therefore, theisolation layer 110 may have a convex upper surface, but aspects of thepresent inventive concept are not limited thereto. In some embodiments,the isolation layer 110 may be etched to have a concave upper surface.

Referring to FIG. 6, in some embodiments, after the etching process, topsurfaces and lateral surfaces of fins F1′ to F4′ may form acute angles.In detail, even if materials having different etching selectivity levelsare used in the etching process of the isolation layer 110, portions ofthe isolation layer 110 and the fins F1′ to F4′ may also be etched.Greater etching may occur at mid portions of the fins F1 to F4 than neartop portions of the fins F1 to F4. Therefore, the top surfaces andlateral surfaces of the fins F1′ to F4′ may have a first angle θ1 or asecond angle θ2, which is smaller than 90 degrees. The magnitude of thefirst angle θ1 or the second angle θ2 may vary according to the kind ofetching gas used in the etching process. With the structures of the finsF1′ to F4′, etching of a spacer 130 or a gate electrode 125 formed onlateral surfaces of the fins F1′ to F4′ (see FIG. 10) can be easilyachieved, but aspects of the present inventive concept are not limitedthereto.

Referring to FIG. 7, a gate insulation layer 122, a gate electrode layer124 and a hard mask layer 126 are sequentially formed on the fins F1 toF4 and the isolation layer 110. The gate insulation layer 122 mayconform to the fins F1 to F4 and the isolation layer 110. The gateinsulation layer 122 may be formed between each of the fins F1 to F4 andthe gate electrode layer 124. The gate insulation layer 122 may beformed between the isolation layer 110 and the gate electrode layer 124.The gate insulation layer 122 may include a high-k material, such asHfO₂, ZrO₂, or TaO₂.

A gate electrode layer 124 may be formed on the gate insulation layer122. The gate electrode layer 124 may include a conductive material. Insome example embodiments of the present inventive concept, the gateelectrode layer 124 may include a highly conductive metal, but aspectsof the present inventive concept are not limited thereto. In someembodiments, for example, the gate electrode layer 124 may include aconductive non-metal, such as polysilicon.

A hard mask layer 126 may be formed on the gate electrode layer 124. Thehard mask layer 126 may include, for example, silicon oxide, siliconnitride, silicon oxynitride, a metal layer, a photo resist, spin onglass (SOG), and/or a spin on hard mask (SOH). The hard mask layer 126may be formed using, for example, a physical vapor deposition process(PVD), a chemical vapor deposition process (CVD), an atomic layerdeposition (ALD) and/or spin coating. It will be appreciated thatembodiments of the present inventive concept are not limited thereto.

Referring to FIG. 8, a hard mask pattern 127 may be formed from the hardmask layer 126 using an etching process. The hard mask pattern 127 mayextend across the fins F1 to F4 along a first direction X.

Referring to FIG. 9, a gate insulation layer 123 and a gate electrode125 may be formed using the hard mask pattern 127 as an etch mask.Accordingly, the gate insulation layer 123 and the gate electrode 125may extend along the first direction X, crossing the fins F1 to F4. Asshown, the second direction Y may be orthogonal to the first directionX, but embodiments of the present inventive concept are not limitedthereto.

Referring to FIG. 10, the spacer 130 is formed on sidewalls of the gateelectrode 125 and sidewalls of top portions of the fins F1 to F4.

For example, an insulation layer is formed on the resultant producthaving the gate electrode 125, and an etch back process is performed tofaun spacers 130. The spacers 130 may expose a top surface of the hardmask pattern 127 and top surfaces of the fins F1 to F4. The spacers 130may include silicon nitride and/or silicon oxynitride.

The spacers 130 may be positioned on at least one side of the gateelectrode 125. In detail, as shown in FIG. 10, the spacers 130 may bepositioned on opposite sides of the gate electrode 125. In FIG. 10, onelateral surface of the spacers 130 is curved, but embodiments of thepresent inventive concept are not limited thereto. Shapes of the spacers130 may vary. For example, in some example embodiments of the presentinventive concept, the spacers 130 may have an I-shaped or an L-shapedcross-section, unlike in FIG. 10.

Referring to FIGS. 11 and 12, a first interlayer insulation layer 142covering only the first region I of the substrate 100 is formed. Thefirst interlayer insulation layer 142 may include a silicon oxide, suchas borosilicate glass (BSG), phosphosilicate glass (PSG),borophosphosilicate glass (BPSG), undoped silicate glass (USG),tetraethylorthosilicate (TEOS), and/or high density plasma CVD (HDP-CVD)silicon oxide.

Top portions of the third fin F3 and the fourth fin F4 on the secondregion II of the substrate 100 are recessed. Accordingly, the third finF3 and the fourth fin F4 positioned at opposite sides of the gateelectrode 125 may have reduced heights. Portions of the spacers 130 maybe etched together with the third fin F3 and the fourth fin F4, butaspects of the present inventive concept are not limited thereto.

First source/drain regions 152 may be formed on the top surfaces of thethird fin F3 and the fourth fin F4 using, for example, epitaxial growth.The epitaxial growth may include an eSiGe process. To form an epitaxiallayer on the substrate 100, solid phase epitaxy (SPE), liquid phaseepitaxy (LPE) and/or vapor phase epitaxy (VPE) may be employed. Forexample, according to first embodiments of the present inventiveconcept, a single crystalline epitaxial layer may be allowed to grow ata temperature in a range of approximately 500° C. to approximately 800 °C. using a source gas including silicon (Si) and/or germanium (Ge).Accordingly, a single crystalline epitaxial layer including silicongermanium (SiGe) is formed on the substrate 100.

Thereafter, in order to stabilize the grown single silicon germanium(SiGe) crystalline epitaxial layer, a heat treatment process may beperformed. The first source/drain regions 152 may include SiGe. Thestructure formed in the second region II may function as a PMOStransistor. In addition, spacers 130 may be positioned under the firstsource/drain regions 152.

Referring to FIGS. 13 to 15, the first interlayer insulation layer 142is removed, and a second interlayer insulation layer 144 covering onlythe second region II is then formed. The second interlayer insulationlayer 144 may include a silicon oxide, such as borosilicate glass (BSG),phosphosilicate glass (PSG), borophosphosilicate glass (BPSG), undopedsilicate glass (USG), tetraethylorthosilicate (TEOS), or high densityplasma CVD (HDP-CVD) silicon oxide.

Top portions of the first fin F1 and the second fin F2 on the firstregion I of the substrate 100 are recessed, thus reducing the height ofthe first fin F1 and the second fin F2 positioned at opposite sides ofthe gate electrode 125. In the recessing, portions of the spacers 130may be etched together with the first fin F1 and the second fin F2, butembodiments of the present inventive concept are not limited thereto.

Second source/drain regions 154 may be formed on the top surfaces of thefirst fin F1 and the second fin F2 using epitaxial growth. The epitaxialgrowth may include an eSiGe process. For example, a single crystallineepitaxial layer may be grown at a temperature in a range ofapproximately 500° C. to approximately 800° C. using a source gasincluding silicon (Si) or silicon carbide (SiC). Accordingly, a singlecrystalline epitaxial layer including silicon (Si) or silicon carbide(SiC) is formed on the substrate 100. Thereafter, in order to stabilizethe grown single crystalline epitaxial layer, a heat treatment processmay be performed. As the result, the second source/drain regions 154 mayinclude silicon (Si) or silicon carbide (SiC). The structure in thefirst region I may function as an NMOS transistor. In addition, spacers130 may be positioned under the second source/drain regions 154.

For a PMOS transistor, the first source/drain regions 152 may include acompressive stress material, such as a material having a greater latticeconstant than silicon (Si), for example, SiGe. The compressive stressmaterial may improve the mobility of carriers of the channel region byapplying a compressive stress to the third and fourth fins F3 and F4.

For an NMOS transistor, the second source/drain regions 154 may includethe same material as the substrate 100 or a tensile stress material. Forexample, when the substrate 100 includes Si, the second source/drainregions 154 may include Si or a material having a smaller latticeconstant than Si (e.g., SiC).

In the above-described embodiments, the PMOS transistor and the NMOStransistor are sequentially formed, but embodiments of the presentinventive concept are not limited thereto. For example, a formingsequence of the PMOS transistor and the NMOS transistor may be varied.In addition, positions of the PMOS transistor and the NMOS transistorformed may also be varied.

Referring to FIG. 16, after the forming of the first and secondsource/drain regions 152 and 154, the gate electrode 125 positionedbetween the second fin F2 and the third fin F3 may be etched to exposethe isolation layer 110. In detail, the gate electrode 125 may be etchedalong the second direction Y to expose the isolation layer 110corresponding to a boundary between the first region I and the secondregion II on the substrate 100. The etching process may be ananisotropic etching process, such as a dry etching process.

Etching processes may include dry and wet etching processes. Wet etchingmay be used to selectively remove a material using a reactive solution.Wet etching may be an isotropic etching process in which a vertical etchrate and a horizontal etch rate are substantially equal.

A dry etching process may use a reactive gas or vapor and, like the wetetching, may be an isotropic etching process. However, a dry etchingprocess that uses a gas or vapor decomposed using plasma may be ananisotropic etching process. Such plasma etching may be anisotropicetching in which the etch rate into the substrate is greater than alateral etch rate. The etching of the gate electrode 125 may beperformed using plasma etching, but embodiments of the present inventiveconcept are not limited thereto.

During the etching process, the gate electrode 125, the gate insulationlayer 123, the hard mask pattern 127 and the spacers 130 may be etchedtogether. In addition, a portion of the isolation layer 110 may also beetched and the portion of the isolation layer 110 may be exposed.Accordingly, a first gate structure 120A may be formed in the firstregion I, a second gate structure 120B may be formed in the secondregion II, and a first trench R1 may be formed between the first gatestructure 120A and the second gate structure 120B. The first gatestructure 120A and the second gate structure 120B may be electricallydisconnected from each other, and may be parts of separate transistors.

As described above, when the gate electrode 125 is etched after theforming of the source/drain regions 152 and 154, the semiconductordevice may be short-circuited when forming the source/drain regions 152and 154. If the epitaxial growth process for the source/drain regions152 and 154 were to be performed after the short-circuiting of thesemiconductor device, failures of the semiconductor device might begenerated, so that characteristics of the semiconductor device might bechanged, as the sidewalls of the gate, source or drain would be exposedduring the epitaxial growth process. However, when the semiconductordevice is short-circuited after the epitaxial growth process isperformed as described above, the likelihood of failure can be reduced,and defects of the sidewalls of the gate can be reduced, therebyimproving the performance of the semiconductor device.

FIGS. 17 to 20 are diagrams illustrating intermediate process steps formanufacturing a semiconductor device according to second embodiments ofthe present inventive concept. Repeated descriptions of previouslydescribed items will be omitted, with the following description focusingon differences between the presently described embodiments andpreviously described embodiments.

Some process steps for manufacturing a semiconductor device according tosecond embodiments of the present inventive concept are substantiallythe same as those described above according to the first embodiments ofthe present inventive concept shown in FIGS. 1 to 15.

Referring to FIG. 17, subsequent to the operations described above withreference to FIG. 15, an interlayer insulation layer 146 is formed onthe structure having first and second source/drain regions 152 and 154.The interlayer insulation layer 146 may be, for example, a silicon oxidelayer. The interlayer insulation layer 146 may be planarized until a topsurface of a gate electrode 125 is exposed. As a result of theplanarization, a hard mask pattern 127 may be removed. The gateelectrode 125 may be used as a dummy gate electrode.

Referring to FIG. 18, the gate insulation layer 123 and the gateelectrode 125 are removed, leaving a trench 161 through which theisolation layer 110 and portions of fins F1 to F4 are exposed.

Referring to FIG. 19, a gate insulation layer 162 and a gate electrode164 are formed in the trench 161. The gate insulation layer 162 mayconform to sidewalls and a bottom surface of the trench 161. The gateelectrode 164, including metal layers MG1 and MG2, may be formed on thegate insulation layer 162.

The gate insulation layer 162 may be formed between the fins F1 to F4and the gate electrode 164. The gate insulation layer 162 may be formedon top portions of the fins F1 to F4. In addition, the gate insulationlayer 162 may be disposed between the gate electrode 164 and theisolation layer 110. The gate insulation layer 162 may include a high-kmaterial having a dielectric constant greater than silicon oxide. Forexample, the gate insulation layer 162 may include HfO₂, ZrO₂, and/orTaO₂.

The gate electrode 164 may extend along the first direction X and crossthe fins Fl to F4. The gate electrode 164 may include metal layers MG1and MG2. The first metal layer MG1 may function to adjust a workfunction, and the second metal layer MG2 may function to fill a spaceformed by the first metal layer MG1. For example, the first metal layerMG1 may include TiN, TaN, TiC, and/or TaC. The second metal layer MG2may include W and/or or Al. In some embodiments, the gate electrode 164may include a non-metal, such as Si or SiGe. The gate electrode 164 maybe formed using, for example, a replacement process, but embodiments ofthe present inventive concept are not limited thereto.

Referring to FIG. 20, a portion of the gate electrode 164 positionedbetween the second fin F2 and the third fin F3 is etched to expose theisolation layer 110. The gate electrode 164 may be etched in a seconddirection Y to expose the isolation layer 110 corresponding to aboundary between the first region I and the second region II on thesubstrate 100. The etching process may be an anisotropic etchingprocess, for example, a dry etching process.

During the etching process, the gate electrode 164, the gate insulationlayer 162 and the spacers 130 may be etched together. In addition, aportion of the isolation layer 110 may also be etched, and a portion ofthe isolation layer 110 may be exposed. In this manner, a first gatestructure 220A may be formed in the first region I, a second gatestructure 220B may be formed in the second region II, and a secondtrench R2 may be formed between the first gate structure 220A and thesecond gate structure 220B. The first gate structure 220A and the secondgate structure 220B may be electrically disconnected from each other,and may be parts of separate transistors.

Operations for manufacturing a semiconductor device according to thesecond embodiments of the present inventive concept may providesubstantially the same results as operations for manufacturing asemiconductor device according to the first embodiments of the presentinventive concept shown in FIG. 16, but embodiments of the presentinventive concept are not limited thereto.

FIGS. 21 to 29 are diagrams illustrating operations for manufacturing asemiconductor device according to third embodiments of the presentinventive concept. Repeated descriptions of previously described contentwill be omitted, with the following description focusing on differencesbetween the present embodiments and previously described embodiments.

Some operations for manufacturing a semiconductor device according tothe third embodiments of the present inventive concept may besubstantially the same as those described above for the firstembodiments of the present inventive concept shown in FIGS. 1 to 10.

Referring to FIG. 21, subsequent to the operations described above withreference to FIG. 10, an interlayer insulation layer 146 is formed onthe structure including the spacers 130. The interlayer insulation layer146 may be, for example, a silicon oxide layer.

The interlayer insulation layer 146 is planarized until a top surface ofa gate electrode 125 is exposed. As the result, the hard mask pattern127 may be removed. The gate electrode 125 may be used as a dummy gateelectrode.

Referring to FIG. 22, the gate insulation layer 123 and the gateelectrode 125 are removed, forming a trench 161 through which theisolation layer 110 and portions of fins F1 to F4 are exposed.

Referring to FIG. 23, a gate insulation layer 162 and a gate electrode164 are formed in the trench 161. The gate insulation layer 162 mayconform to sidewalls and a bottom surface of the trench 161. The gateelectrode 164 including metal layers MG1 and MG2 may be formed on thegate insulation layer 162.

The gate electrode 164 may extend along the first direction X and crossthe fins F1 to F4. The gate electrode 164 may be formed by stacking twoor more metal layers MG1 and MG2. The first metal layer MG1 may functionto adjust a work function, and the second metal layer MG2 may functionto fill a space formed by the first metal layer MG1.

Referring to FIGS. 24 and 25, a first interlayer insulation layer 142covering only the first region I of the substrate 100 is formed. Thefirst interlayer insulation layer 142 may include a silicon oxide, suchas borosilicate glass (BSG), phosphosilicate glass (PSG),borophosphosilicate glass (BPSG), undoped silicate glass (USG),tetraethylorthosilicate (TEOS), or high density plasma CVD (HDP-CVD)silicon oxide.

Top portions of the third fin F3 and the fourth fin F4 on the secondregion II of the substrate 100 are recessed, such that the third fin F3and the fourth fin F4 positioned at opposite sides of the gate electrode164 may have reduced heights. In the recessing, portions of the spacers130 may be etched together with the third fin F3 and the fourth fin F4,but embodiments of the present inventive concept are not limitedthereto.

First source/drain regions 152 may be formed on the top surfaces of thethird fin F3 and the fourth fin F4 using epitaxial growth. The epitaxialgrowth may include an eSiGe process. The structure in the second regionII may function as a PMOS transistor. The spacers 130 may be positionedunder the first source/drain regions 152.

Referring to FIGS. 26 to 28, the first interlayer insulation layer 142is removed, and a second interlayer insulation layer 144 covering onlythe second region II of the substrate 100 is then formed.

Top portions of the first fin F1 and the second fin F2 on the firstregion I of the substrate 100 are recessed. Accordingly, the first finF1 and the second fin F2 at opposite sides of the gate electrode 164 mayhave reduced heights. In the recessing, portions of the spacers 130 maybe etched together with the first fin Fl and the second fin F2, butembodiments of the present inventive concept are not limited thereto.

Second source/drain regions 154 may be formed on the top surfaces of thefirst fin Fl and the second fin F2 using epitaxial growth. The epitaxialgrowth may include an eSiGe process. The second source/drain region 154may include silicon (Si) or silicon carbide (SiC). The structure formedon first region I may function as an NMOS transistor. Spacers 130 may bepositioned under the second source/drain regions 154.

When the semiconductor device is a PMOS transistor, the source/drainregions 152 and 154 may include a compressive stress material. Forexample, the compressive stress material may be a material having alarger lattice constant than silicon (Si), such as SiGe. The compressivestress material may improve the mobility of carriers of a channel regionby applying the compressive stress to the third and fourth fins F3 andF4. When the semiconductor device is an NMOS transistor, thesource/drain regions 152 and 154 may include the same material as thesubstrate 100 or a tensile stress material. For example, when thesubstrate 100 includes Si, the first source/drain region 152 may includeSi or a material having a smaller lattice constant than Si (e.g., SiC).

In the above-described embodiments, the PMOS transistor and the NMOStransistor are sequentially formed, but embodiments of the presentinventive concept are not limited thereto. Generally, a forming sequenceof the PMOS transistor and the NMOS transistor may be varied. Inaddition, positions of the PMOS transistor and the NMOS transistor mayalso be varied.

Referring to FIG. 29, the gate electrode 164 positioned between thesecond fin F2 and the third fin F3 may be etched to expose the isolationlayer 110. The gate electrode 164 may be etched along the seconddirection Y to expose the isolation layer 110 at a positioncorresponding to a boundary between the first region I and the secondregion II on the substrate 100. The etching process may be ananisotropic etching process, for example, a dry etching process. Duringthe etching process, the gate electrode 164, the gate insulation layer162 and the spacers 130 may be etched together. In addition, theisolation layer 110 may also be etched to expose a portion of theisolation layer.

In this manner, a first gate structure 320A may be formed in the firstregion I, a second gate structure 320B may be formed in the secondregion II, and a third trench R3 may be formed between the first gatestructure 320A and the second gate structure 320B. The first gatestructure 320A and the second gate structure 320B may be electricallydisconnected from each other, and may function as parts of separatetransistors.

The operations for manufacturing a semiconductor device according to thethird embodiments of the present inventive concept may producesubstantially the same results as the operations for manufacturing asemiconductor device according to the first embodiments of the presentinventive concept shown in FIG. 16, but embodiments of the presentinventive concept are not limited thereto.

FIGS. 30 to 32 illustrate semiconductor according to some exampleembodiments of the present inventive concept. Repeated descriptions ofpreviously described content will be omitted and the followingdescription will focus on differences between the present embodimentsand previously described embodiments.

FIG. 30 is a layout view of the semiconductor device. Referring to FIG.30, the semiconductor device includes a plurality of fins F1 to F4formed on a substrate 100 and a plurality of gate structures 421, 422,423 and 424. The plurality of fins F1 to F4 may extend lengthwise alonga second direction Y. The plurality of gate structures 421, 422, 423 and424 may extend lengthwise along a first direction X, crossing the finsFl to F4.

The plurality of gate structures 421, 422, 423 and 424 may be separatedfrom each other by a fourth trench R4 or a fifth trench R5 aftersource/drain regions 152 and 154 are formed by epitaxial growth. Thefourth trench R4 or the fifth trench R5 may be formed by an anisotropicdry etching process.

The fourth trench R4 or the fifth trench R5 may expose the isolationlayer 110. In other words, the fourth trench R4 or the fifth trench R5may extend to a top surface of the isolation layer 110. The fourthtrench R4 and the fifth trench R5 may be formed so as to cross eachother, but embodiments of the present inventive concept are not limitedthereto.

The fourth trench R4 and the fifth trench R5 may electrically disconnectthe fins F1 to F4 and the gate electrode 125 formed on the substrate 100by the respective regions. For example, the fourth trench R4 and thefifth trench R5 may separate a first region 420A to a fourth region 420Dfrom each other to short-circuit the device.

FIG. 31 is a cross-sectional view taken along the line A-A and FIG. 32is a cross-sectional view taken along the line B-B. Referring to FIGS.31 and 32, the plurality of fins F1 to F4 may be formed on the substrate100 and the isolation layer 110 may be formed between respective ones ofthe plurality of fins F1 to F4. The isolation layer 110 may include STIor DTI. A top surface of the isolation layer 110 may be lower than topsurfaces of the fins Fl to F4. Although not shown, more etching mayoccur to side portions of the isolation layer 110 near the fins F1 to F4than to center portions of the isolation layer 110 between respectiveones of the fins F1 to F4. In addition, top surfaces and lateralsurfaces of the fins F1 to F4 may form acute angles, but embodiments ofthe present inventive concept are not limited thereto.

A gate insulation layer 423, a gate electrode 425, and a hard maskpattern 427 may be formed on the fins F1 to F4 and the isolation layer110. A spacer 430 may be formed on sidewalls of the gate electrode 425and sidewalls of top portions of the fins F1 to F4.

Source/drain regions 452 and 454 may be formed on at opposite sides ofthe gate electrode 425. The source/drain regions 452 and 454 may beformed after recessing portions of the fins F1 to F4. The fins F1 to F4may be recessed on opposite sides of the gate electrode 425. Thesource/drain regions 452 and 454 may be formed at opposite sides of thegate electrode 425 using an epitaxial process. The source/drain regions452 and 454 may come into contact with portions of the spacers 430contacting lateral surfaces of the gate electrode 425.

An interlayer insulation layer 446 may be formed on the resultantproduct having the gate electrode 425 and the source/drain regions 452and 454. A fourth trench R4 and a fifth trench R5 for short-circuitingeach of transistors formed in the first to fourth regions (420A˜420D)may be formed. The fourth trench R4 and the fifth trench R5 may expose atop surface of the isolation layer 110.

As described above, in a case where the fourth trench R4 and the fifthtrench R5 are formed after the source/drain regions 452 and 454 areformed, the semiconductor device can be short-circuited by therespective regions. If the epitaxial growth process is performed afterthe short-circuiting of the semiconductor device, failures of thesemiconductor device may be generated, so that characteristics of thesemiconductor device may be changed as the sidewalls of the gate, sourceor drain are exposed during the epitaxial growth process. However, whenthe semiconductor device is short-circuited after the epitaxial growthprocess is performed, the failures can be reduced, and defects of thesidewalls of the gate can be reduced, thereby improving the performanceof the semiconductor device.

FIG. 33 is a circuit view illustrating semiconductor devices accordingto some example embodiments of the inventive concept and FIG. 34 is alayout view illustrating semiconductor devices according to some exampleembodiments of the present inventive concept. FIG. 35 illustratesselected portions of fins and gate structures from the layout view ofFIG. 34. Generally, embodiments of the present inventive concept can beapplied to all devices including general logic devices using fin-typetransistors. However, FIGS. 33 to 35 illustrate SRAMs as an example.

Referring to FIG. 33, a semiconductor device 10 according to someexample embodiments of the present inventive concept may include a pairof inverters INV1 and INV2 connected in parallel between a power supplynode Vcc and a ground node Vss, and a first pass transistor PS1 and asecond pass transistor PS2 connected to output nodes of the invertersINV1 and INV2. The first pass transistor PS1 and the second passtransistor PS2 may be connected to a bit line BL and a complementary bitline /BL. Gates of the first pass transistor PS1 and the second passtransistor PS2 may be connected to a word line WL.

The first inverter INV1 includes a first pull-up transistor PU1 and afirst pull-down transistor PD1 connected in series, and the secondinverter INV2 includes a second pull-up transistor PU2 and a secondpull-down transistor PD2 connected in series. The first pull-uptransistor PU1 and the second pull-up transistor PU2 may be PMOStransistors, and the first pull-down transistor PD1 and the secondpull-down transistor PD2 may be NMOS transistors. To provide a latchcircuit, an input node of the first inverter INV1 is connected to anoutput node of the second inverter INV2 and an input node of the secondinverter INV2 is connected to an output node of the first inverter INV1.

Referring to FIGS. 33 to 35, a first fin F1, a second fin F2, a thirdfin F3 and a fourth fin F4 are spaced apart from one another and extendlengthwise in one direction (e.g., in an up-down direction of FIG. 34).The second fin F2 and the third fin F3 may be shorter than the first finF1 and the fourth fin F4.

A first gate electrode 551, a second gate electrode 552, a third gateelectrode 553, and a fourth gate electrode 554 extend along anotherdirection (e.g., in a left-right direction of FIG. 34) to intersect thefirst fin F1 to the fourth fin F4. In detail, the first gate electrode551 completely intersects the first fin F1 and the second fin F2 whilepartially overlapping an end of the third fin F3. The third gateelectrode 553 completely intersects the fourth fin F4 and the third finF3 while partially overlapping an end of the second fin F2. The secondgate electrode 552 and the fourth gate electrode 554 are formed tointersect the first fin Fl and the fourth fin F4, respectively.

As shown FIG. 34, the first pull-up transistor PU1 is disposed in thevicinity of an intersection of the first gate electrode 551 and thesecond fin F2, the first pull-down transistor PD1 is disposed in thevicinity of an intersection of the first gate electrode 551 and thefirst fin F1, and the first pass transistor PS1 is disposed in thevicinity of an intersection of the second gate electrode 552 and thefirst fin F1. The second pull-up transistor PU2 is disposed in thevicinity of an intersection of the third gate electrode 553 and thethird fin F3, the second pull-down transistor PD2 is disposed in thevicinity of an intersection of the third gate electrode 553 and thefourth fin F4, and the second pass transistor PS2 is disposed in thevicinity of an intersection of the fourth gate electrode 554 and thefourth fin F4.

Although not specifically shown, recesses may be formed at oppositesides of the respective intersections of the first to fourth gateelectrodes 551-554 and the first to fourth fins F1, F2, F3 and F4, andsources/drains may be formed in the recesses. In addition, a pluralityof contacts 561 may be formed.

A first shared contact 562 may connect the second fin F2, the third gateelectrode F5, the third gate structure 553 and a wiring 571. A secondshared contact 563 may connect the third fin F3, the first gateelectrode 551 and a wiring 572.

The first pull-up transistor PU1, the first pull-down transistor PD1,the first pass transistor PS1, the second pull-up transistor PU2, thesecond pull-down transistor PD2, and the second pass transistor PS2 maybe fabricated using semiconductor device manufacturing operationsaccording to the example embodiments of the present inventive concept.That is to say, the respective transistors may cause short-circuits tothe semiconductor devices after performing epitaxial growth on thesources or drains.

Hereinafter, an electronic system including the semiconductor devicesmanufactured by semiconductor device manufacturing methods according tosome example embodiments of the present inventive concept will bedescribed. FIG. 36 is a schematic block diagram illustrating anelectronic system including the semiconductor devices manufactured bysemiconductor device manufacturing methods according to some exampleembodiments of the present inventive concept.

Referring to FIG. 36, the electronic system may include a controller610, an interface 620, an input/output device (I/O) 630, a memory 640, apower supply 650 and a bus 660.

The controller 610, the interface 620, the I/O 630, the memory 640,and/or the power supply 650 may be connected to each other through thebus 660. The bus 660 corresponds to a path through which data moves.

The controller 610 may include at least one of a microprocessor, adigital signal processor, a microcontroller, and logic elements capableof functions similar to those of these elements.

The interface 620 may perform functions of transmitting data to acommunication network or receiving data from the communication network.The interface 620 may be wired or wireless. For example, the interface620 may include an antenna or a wired/wireless transceiver, and so on.

The I/O 630 may include a keypad, a display device, and so on.

The memory 640 may store data and/or commands. The semiconductor devicesaccording to some example embodiments of the present inventive conceptmay be provided as some components of the memory 640.

The power supply 650 may convert externally applied power to supply theconverted power to various components 610 to 640.

FIG. 37 is a schematic block diagram illustrating an application exampleof an electronic system including the semiconductor devices manufacturedby semiconductor device manufacturing methods according to some exampleembodiments of the present inventive concept.

Referring to FIG. 37, the electronic system may include a centralprocessing unit (CPU) 710, an interface 720, a peripheral device 730, amain memory 740, a secondary memory 750, and a bus 760.

The CPU 710, the interface 720, the peripheral device 730, the mainmemory 740, and the secondary memory 750 may be connected to each otherthrough the bus 760. The bus 760 may correspond to a path through whichdata moves.

The CPU 710, including a controller, an operation device, etc., mayexecute a program and process data.

The interface 720 may transmit data to a communication network or mayreceive data from the communication network. The interface 720 may beconfigured in a wired/wireless manner. For example, the interface 720may be an antenna or a wired/wireless transceiver.

The peripheral device 730, including a mouse, a keyboard, a displaydevice, a printer, etc., may input/output data.

The main memory 740 may transceive data to/from the CPU 710 and maystore data and/or commands required to execute the program. Thesemiconductor memory devices according to some example embodiments ofthe present inventive concept may be provided as some components of themain memory 740.

The secondary memory 750, including a nonvolatile memory, such as afloppy disk, a hard disk, a CD-ROM, or a DVD, may store the data and/orcommands. The secondary memory 750 may store data even in an event ofpower interruption of the electronic system.

FIGS. 38 to 40 illustrate example semiconductor systems to which thesemiconductor devices manufactured by semiconductor device manufacturingmethods according to some exemplary embodiments of the present inventiveconcept can be applied.

FIG. 38 illustrates an example in which a semiconductor device accordingto an embodiment of the present inventive concept is applied to a tabletPC (1100), FIG. 39 illustrates an example in which a semiconductordevice according to an embodiment of the present inventive concept isapplied to a notebook computer (1200), and FIG. 40 illustrates anexample in which a semiconductor device according to an embodiment ofthe present inventive concept is applied to a smart phone (1300). Atleast one of the semiconductor device manufacturing methods according tosome example embodiments of the present inventive concept can beemployed to the tablet PC 1100, the notebook computer 1200, the smartphone 1300, and the like.

It is obvious to one skilled in the art that the semiconductor devicemanufacturing methods according to some example embodiments of thepresent inventive concept may also be applied to other IC devices notillustrated herein. In the above-described example embodiments, only thetablet PC 1100, the notebook computer 1200 and the smart phone 1300 havebeen exemplified as the semiconductor devices according to the exampleembodiments of the present inventive concept, but aspects of the presentinventive concept are not limited thereto. In some example embodimentsof the present inventive concept, the nonvolatile memory system may beimplemented as a computer, an ultra mobile personal computer (UMPC), awork station, a net-book, a personal digital assistant (PDA), a portablecomputer, a web tablet, a wireless phone, a mobile phone, a smart phone,an e-book, a portable multimedia player (PMP), a potable game console, anavigation device, a black box, a digital camera, a 3-dimensional (3D)television, a digital audio recorder, a digital audio player, a digitalpicture recorder, a digital picture player, a digital video recorder, adigital video player, or a device capable of transmitting/receivinginformation in wireless environments, one of various electronic devicesconstituting a home network, one of various electronic devicesconstituting a computer network, one of various electronic devicesconstituting a telematics network, RFID devices, or embedded computingsystems.

While the present inventive concept has been particularly shown anddescribed with reference to exemplary embodiments thereof, it will beunderstood by those of ordinary skill in the art that various changes inform and details may be made therein without departing from the spiritand scope of the present inventive concept as defined by the followingclaims. It is therefore desired that the present exemplary embodimentsbe considered in all respects as illustrative and not restrictive,reference being made to the appended claims rather than the foregoingdescription to indicate the scope of the invention.

What is claimed is:
 1. A method of manufacturing a semiconductor device,the method comprising: forming spaced apart first and second fins on asubstrate; forming an isolation layer on the substrate between the firstand second fins; forming a dummy gate on the isolation layer andcrossing the first and second fins; forming source/drain regions on thefirst and second fins on first and second sides of the dummy gate;removing the dummy gate to form a trench; forming a gate structure inthe trench; and removing a portion of the gate structure between thefirst and second fins to form respective first and second gatestructures on respective ones of the first and second fins.
 2. Themethod of claim 1, wherein the gate structure comprises a gateinsulation layer, a first metal layer and a second metal layer, andwherein the gate structure is formed after formation of the source drainregions.
 3. The method of claim 1, wherein removing a portion of thegate structure between the first and second fins to form respectivefirst and second gate structures on respective ones of the first andsecond fins comprises anisotropic dry etching the gate structure.